1. Field of Invention
The present invention relates to intercoms and, more specifically, to a wirefree intercom having improved transmission quality.
2. Description of Prior Art
Conventional intercoms are powered by the wall outlet and transmit the voice of the speaker over the wires installed throughout the home. These intercoms use power line modulation techniques and have limited ranges due to the need for physical attachment to the power lines in the wall, as well as when the possibility of phase changes in the power connection that may interfere with the signal. In addition, the sound quality is often limited in such systems, and when there is a motor (such a hair dryer or vacuum cleaner) also in operation on the circuit, the signal is often distorted or destroyed.
Wireless intercoms use a radio signal and, like conventional intercoms, are powered by a wall outlet. These devices usually employ Family Radio Service (FRS) radio technology and have decent range capabilities. However, such devices do not provide security when multiple devices are employed in a dwelling. For example, if there are five units in a home and all are set to the same security number, each unit allows for reception of a conversation occurring between any other two units. In a business environment, this loss of security is not desirable. Additionally, such devices consume too much power and are thus not feasibly implemented without a direct power connection to a wall outlet. Some wireless intercoms use both wall power and batteries. In addition to limitation described above with respect to wireless intercoms, the batteries in such systems will only last about a day or two when the device is left on.